Medical imaging has been an expanding field for several decades. With increasing diagnostic tools, increasing population, more wide-spread access to medical treatment, and the desirability of sharing information between doctors and professionals, medical imaging is likely to continue growing at a rapid rate. To address this continued growth, and the subsequent inconveniences of paper and other fixed forms of medical image storage, the medical community has increasingly turned to digital forms of image storage.
Picture Archiving and Communications Systems (PACS) are a common example of a digital image system. Enterprise PACS deployments, such as those found in a hospital, provide a centralized means of searching, retrieving and storing images using the Digital Imaging and Communications in Medicine (DICOM) protocol.
According to the DICOM protocol, each digital image is stored as a DICOM object which includes the raw image data as well as associated meta-data such as the name of the patient of whom the image was taken and the date on which the image was captured. For each originally captured image there may be more than one associated DICOM image object.
Other DICOM objects contain information regarding the manner in which an image is to be displayed or clinical information which may be related to an image or images. These types of DICOM objects do not include raw image data but may include references to DICOM image objects which do include image data.
The DICOM objects stored in digital image systems such as PACS are often organized into groups, called studies. Each study normally includes the DICOM objects which relate to one particular patient for a particular purpose. One study may include many different types of DICOM objects, with various references connecting them.
For various reasons, DICOM objects from one study may need to be moved or copied to a different study, such as when a study is merged, split, or segmented. This is often done by creating a duplicate or “clone” of the original object in the target study and, if necessary, deleting the original object from the source study. Problems may arise, however, when a cloned object includes references to, or is referenced by, other objects in the source study. If these other objects are not cloned along with the object to which they relate, information may be lost. Similar problems may arise when deleting objects from the source study. If an object which references or is referenced by another object is deleted then that reference will be broken.
Previous solutions to these problems put the burden on the user to select which objects to clone and which objects to leave in the original study. This can be both time consuming and error prone as the user may not be aware of all the relationships between the objects and some objects, particularly those which do not include raw image data, may not be visible to the user. Another possible solution to this problem is to move the original object to the target study rather than cloning it, thus preserving references between the objects. However, this violates several standards and causes significant other problems. For instance, according to one DICOM standard, each time a change is made to a study, a new DICOM object needs to be generated. By moving the original objects to the target study rather than creating new objects, this DICOM standard is violated.
Thus, it would be desirable to have a method for automatically selecting data objects which are in some way associated with a set of cloned data objects to be similarly cloned while still protecting those objects which must remain in the source study from deletion. This would reduce the burden on the user to decipher the maze of references within a study and allow both the cloned objects and the original objects to function correctly with no loss of information.